DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 280100
SWODY1
SPC AC 280058

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0758 PM CDT WED JUN 27 2012

VALID 280100Z - 281200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
UPPER-AIR PATTERN OVER CONUS REMAINS DOMINATED BY LARGE ANTICYCLONE
CENTERED OVER CENTRAL PLAINS...WITH RIDGING NNEWD ACROSS SRN HUDSON
BAY...EWD OVER SRN APPALACHIANS AND WSWWD OVER NRN SONORA. UPPER
LOW OVER MAINE/NEW BRUNSWICK SHOULD MEANDER SLOWLY/ERRATICALLY NEWD
THROUGH REMAINDER PERIOD...WHILE SMALLER UPPER LOW OVER SK/MB BORDER
CROSSES NRN MB. POSITIVELY TILTED/LOW-AMPLITUDE SHORTWAVE TROUGH IS
EVIDENT FROM BLACK HILLS REGION SSWWD ACROSS 4-CORNERS REGION. THIS
TROUGH IS EXPECTED TO MOVE ENEWD TO UPPER MS VALLEY...ERN NEB AND
NRN KS BY END OF PERIOD...BECOMING MORE POSITIVELY TILTED DUE TO
FASTER TRANSLATION OF NRN SEGMENT OF ASSOCIATED 500-MB VORTICITY
BANNER.

AT SFC...23Z ANALYSIS SHOWED WAVY FRONTAL ZONE FROM LS/UPPER MI SWWD
ACROSS SRN MN...ERN/SRN NEB AND NWRN KS. WRN PORTION OF FRONT
BECOMES DIFFUSED BY CONVECTIVE OUTFLOWS ACROSS ERN CO. NRN PORTION
OF FRONT SHOULD MOVE EWD ACROSS LS/WI THROUGH PERIOD...WHILE
REMAINDER BECOMES QUASISTATIONARY OVER CENTRAL PLAINS....MODULATED
LOCALLY BY TSTM OUTFLOWS.

...AZ AND CENTRAL HIGH PLAINS TO MN...
POSITIVELY TILTED SHORTWAVE TROUGH ALOFT ALSO DEMARCATES WRN EDGE OF
PLUME OF LOW-MIDDLE LEVEL MOISTURE CONTRIBUTING TO CONVECTION FROM
SRN AZ TO SD/WRN MN. SCATTERED TO WIDELY SCATTERED TSTMS SHOULD
CONTINUE OVER AZ...BECOMING WIDELY SCATTERED TO ISOLATED NEWD OVER
CENTRAL HIGH PLAINS...THEN ISOLATED FARTHER NE. 00Z SOUNDINGS SHOW
STRENGTHENING CAP WITH NEWD EXTENT FROM HIGH PLAINS...INVOF FRONTAL
ZONE...AS ELEVATION LESSENS BENEATH EML. PLUME OF 16-19 DEG C 700
MB TEMPS FROM LBF-OAX-MPX IS SYMPTOMATIC OF STG CAPPING BELOW THAT
LEVEL...EVIDENT IN OBSERVED RAOBS. A FEW GUSTS NEAR SVR LIMITS
STILL ARE POSSIBLE...ESPECIALLY OVER PRECONVECTIVE AIR MASS
REMAINING IN PARTS OF CENTRAL HIGH PLAINS AND SWRN/S-CENTRAL AZ.
ALREADY MRGL SVR THREAT WITH EXISTING CONVECTION OVER HIGHER TERRAIN
SHOULD DIMINISH WITH TIME THROUGH REMAINDER EVENING...AS COMBINATION
OF SPREADING OUTFLOWS AND DIABATIC SFC COOLING CONTRIBUTE TO
BOUNDARY-LAYER STABILIZATION.

..EDWARDS.. 06/28/2012

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